publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
|---|---|---|---|
2013-11-20 | X-ray time delays in the Narrow Line Seyfert 1 galaxy PG 1244+026 | We analyse the X-ray time-lags in the Narrow Line Seyfert 1 (NLS1) galaxy PG
1244+026 ($M_{\rm BH}\sim 10^7 M_{\rm sun}$, $L/L_{\rm Edd}\sim 1$). The time
delay between the soft (0.3--0.7~keV) and harder (1.2--4.0~keV) variations
shows shows the well established switch from hard lags at low frequencies to
soft lags at ... | 1311.5165v2 |
2013-11-21 | L4Fe2As2Te1-xO4-yFy (L = Pr, Sm, Gd): a layered oxypnictide superconductor with Tc up to 45 K | The synthesis, structural and physical properties of iron lanthanide
oxypnictide superconductors, L4Fe2As2Te1-xO4 (L = Pr, Sm, Gd), with transition
temperature at ~ 25 K are reported. Single crystals have been grown at high
pressure using cubic anvil technique. The crystal structure consists of layers
of L2O2 tetrahedr... | 1311.5437v2 |
2013-11-22 | Magnetic phase transitions and superconductivity in strained FeTe | The influence of hydrostatic pressure and ab-plane strain on the magnetic
structure of FeTe is investigated from first principles. The results of
calculations reveal a phase transition from antiferromagnetic double-stripe
ordering at ambient pressure to ferromagnetic ordering at 2 GPa, or under
compressive strain reduc... | 1311.5732v1 |
2013-11-22 | Coherent emission of $γ$ quanta by synchrotron radiation excited nuclei: geometry of nearly backward scattering | A possibility of further development of Synchrotron M\"{o}ssbauer Source
(SMS) of $^{57}$Fe 14.4 keV radiation is considered. The principles and
detailed description of the SMS device is given in Refs. Phys. Rev. A 84,
053851 (2011) G. V. Smirnov et al, J. Synchrotron Rad., v. 19, 559 (2012) V.
Potapkin et al. The perf... | 1311.5771v1 |
2013-11-24 | Temperature and high strain rate dependence of tensile deformation behavior in single crystal iron from dislocation dynamics simulations | We conduct dislocation dynamics (DD) simulations of Fe periodic single
crystals under tensile load at several high strain rates and temperatures. The
simulations are enabled by the recent development of temperature-dependent
dislocation mobility relations obtained from atomistic calculations. The
plastic evolution in t... | 1311.6173v1 |
2013-11-26 | Field Measurement for Superconducting Magnets of ADS Injector I | The superconducting solenoid magnet prototype for ADS injection-I had been
fabricated in Beijing Qihuan Mechanical and Electric Engineer Company and
tested in Haerbin Institute of Technology (HIT) in Nov, 2012. Batch magnet
production was processed after some major revision from the magnet prototype,
they include: remo... | 1311.6596v1 |
2013-11-28 | From supernovae to neutron stars | The gravitational collapse, bounce, the explosion of an iron core of an 11.2
$M_{\odot}$ star is simulated by two-dimensional neutrino-radiation
hydrodynamic code. The explosion is driven by the neutrino heating aided by
multi-dimensional hydrodynamic effects such as the convection. Following the
explosion phase, we co... | 1311.7249v2 |
2013-12-01 | Chemical Bonding in Aqueous Ferrocyanide: Experimental and Theoretical X-ray Spectroscopic Study | Resonant inelastic X-ray scattering (RIXS) and X-ray absorption (XA)
experiments at the iron L- and nitrogen K-edge are combined with high-level
first principles restricted active space self-consistent field (RASSCF)
calculations for a systematic investigation of the nature of the chemical bond
in potassium ferrocyanid... | 1312.0236v1 |
2013-12-04 | Ray-tracing in pseudo-complex General Relativity | Motivated by possible observations of the black hole candidate in the center
of our galaxy and the galaxy M87, ray-tracing methods are applied to both
standard General Relativity (GR) and a recently proposed extension, the
pseudo-complex General Relativity (pc-GR). The correction terms due to the
investigated pc-GR mod... | 1312.1170v2 |
2013-12-09 | Point contact spectroscopy in Fe-based superconductors: recent advancements and future challenges | Iron-based superconductors (FeSC) present an unprecedented variety of
features both in the superconducting and in the normal state. Different
families differ in the value of the critical temperature, in the shape of the
Fermi surface, in the existence or absence of quasi-nesting conditions, in the
range of doping in wh... | 1312.2527v1 |
2013-12-10 | On the origin of variable structures in the winds of hot luminous stars | Examination of the temporal variability properties of several strong optical
recombination lines in a large sample of Galactic Wolf-Rayet (WR) stars reveals
possible trends, especially in the more homogeneous WC than the diverse WN
subtypes, of increasing wind variability with cooler subtypes. This could imply
that a s... | 1312.2864v1 |
2013-12-10 | Spectrum splitting of bimagnon excitations in a spatially frustrated Heisenberg antiferromagnet revealed by resonant inelastic x-ray scattering | We perform a comprehensive analysis of the bimagnon resonant inelastic x-ray
scattering (RIXS) intensity spectra of the spatially frustrated Jx-Jy-J2
Heisenberg model on a square lattice in both the antiferromagnetic and the
collinear antiferromagnetic phase. We study the model for strong frustration
and significant sp... | 1312.2876v2 |
2013-12-12 | Impact of electronic correlations on the equation of state and transport in $ε$-Fe | We have obtained the equilibrium volumes, bulk moduli, equations of state of
the ferromagnetic cubic $\alpha$ and paramagnetic hexagonal $\epsilon$ phases
of iron in close agreement with experiment using an ab initio dynamical
mean-field theory approach. The local dynamical correlations are shown to be
crucial for a su... | 1312.3654v1 |
2013-12-13 | Phosphorus in the Young Supernova Remnant Cassiopeia A | Phosphorus ($^{31}$P), which is essential for life, is thought to be
synthesized in massive stars and dispersed into interstellar space when these
stars explode as supernovae (SNe). Here we report on near-infrared
spectroscopic observations of the young SN remnant Cassiopeia A, which show
that the abundance ratio of ph... | 1312.3807v1 |
2013-12-16 | Optical conductivity of nodal metals | Fermi liquid theory is remarkably successful in describing the transport and
optical properties of metals; at frequencies higher than the scattering rate,
the optical conductivity adopts the well-known power law behavior
$\sigma_1(\omega) \propto \omega^{-2}$. We have observed an unusual non-Fermi
liquid response $\sig... | 1312.4466v1 |
2013-12-20 | Ultrafast modulation of the chemical potential in BaFe$_2$As$_2$ by coherent phonons | Time- and angle-resolved extreme ultraviolet photoemission spectroscopy is
used to study the electronic structure dynamics in BaFe$_2$As$_2$ around the
high-symmetry points $\Gamma$ and $M$. A global oscillation of the Fermi level
at the frequency of the $A_{1g}$(As) phonon mode is observed. It is argued that
this beha... | 1312.6025v1 |
2013-12-23 | Heat capacity jump at T_c and pressure derivatives of superconducting transition temperature in the Ba(1-x)NaxFe2As2 (0.1 <= x <= 0.9) series | We present the evolution of the initial (up to ~ 10 kbar) hydrostatic,
pressure dependencies of T_c and of the ambient pressure jump in the heat
capacity associated with the superconducting transition as a function of Na -
doping in the Ba(1-x)NaxFe2As2 family of iron-based superconductors. For Na
concentrations 0.15 <... | 1312.6705v1 |
2014-01-07 | The polluted atmospheres of cool white dwarfs and the magnetic field connection | We present an analysis of X-Shooter spectra of the polluted hydrogen-rich
white dwarfs (DAZ) NLTT 888 and NLTT 53908. The spectra of NLTT 53908 show
strong, Zeeman-split calcium lines (CaII H&K and Ca I $\lambda 4226$) and the
star appears to be a close relative of the polluted magnetic white dwarf (DAZH)
NLTT 10480, w... | 1401.1249v1 |
2014-01-10 | The Iron K Line Profile of IRAS 18325-5926 | IRAS 18325-5926 is an X-ray bright, Compton-thin, type-2 Seyfert galaxy and
it was the first Seyfert 2 in which the presence of a broad Fe K-alpha emission
line was claimed. However, although the structure of the Fe line appears broad,
there is tentative evidence that it may comprise multiple lines. Nevertheless,
previ... | 1401.2420v1 |
2014-01-14 | Ipopv2: Photoionization of Ni XIV -- a test case | Several years ago, M. Asplund and coauthors (2004) proposed a revision of the
Solar composition. The use of this new prescription for Solar abundances in
standard stellar models generated a strong disagreement between the predictions
and the observations of Solar observables. Many claimed that the Standard Solar
Model ... | 1401.3122v1 |
2014-01-16 | Terzan 5: a pristine fragment of the Galactic Bulge? | Terzan 5 is a stellar system located in the inner Bulge of the Galaxy and has
been historically catalogued as a globular cluster. However, recent photometric
(Ferraro et al. 2009) and spectroscopic (Origlia et al. 2011; Origlia et al.
2013) investigations have shown that it hosts at least three stellar
populations with... | 1401.3962v1 |
2014-01-20 | Total and Partial Fragmentation Cross-Section of 500 MeV/nucleon Carbon Ions on Different Target Materials | By using an experimental setup based on thin and thick double-sided
microstrip silicon detectors, it has been possible to identify the
fragmentation products due to the interaction of very high energy primary ions
on different targets. Here we report total and partial cross-sections measured
at GSI (Gesellschaft fur Sc... | 1401.4897v1 |
2014-01-21 | Tunable VUV laser based spectrometer for Angle Resolved Photoemission Spectroscopy (ARPES) | We have developed an angle-resolved photoemission spectrometer with tunable
VUV laser as a photon source. The photon source is based on the fourth harmonic
generation of a near IR beam from a Ti:sapphire laser pumped by a CW green
laser and tunable between 5.3eV and 7eV. The most important part of the set-up
is a compa... | 1401.5404v1 |
2014-01-21 | Dramatic Changes in the Electronic Structure Upon Transition to the Collapsed Tetragonal Phase in CaFe2As2 | We use angle-resolved photoemission spectroscopy (ARPES) and density
functional theory (DFT) calculations to study the electronic structure of
CaFe$_2$As$_2$ in previously unexplored collapsed tetragonal (CT) phase. This
unusual phase of the iron arsenic high temperature superconductors was hard to
measure as it exists... | 1401.5416v1 |
2014-01-22 | The effect of exceptionally high fluorine doping on the anisotropy of single crystalline SmFeAsO1-xFx | We succeeded in growing single crystalline SmFeAsO1-xFx with exceptionally
high fluorine concentration by using a CsCl flux method. Comparing to
conventional flux methods, this method can introduce about double the amount of
fluorine into the oxygen site. The obtained single crystal shows the highest
superconducting tr... | 1401.5611v2 |
2014-01-28 | Phase Transformation Dynamics in Porous Battery Electrodes | Porous electrodes composed of multiphase active materials are widely used in
Li-ion batteries, but their dynamics are poorly understood. Two-phase models
are largely empirical, and no models exist for three or more phases. Using a
modified porous electrode theory based on non-equilibrium thermodynamics, we
show that ex... | 1401.7072v2 |
2014-01-29 | The poisoning effect of Mn in LaFe(1-x)Mn(x)AsO(0.89)F(0.11): unveiling a quantum critical point in the phase diagram of iron-based superconductors | A superconducting-to-magnetic transition is reported for
LaFe$_{1-x}$Mn$_x$AsO$_{0.89}$F$_{0.11}$ where a per thousand amount of Mn
impurities is dispersed. By employing local spectroscopic techniques like muon
spin rotation (muSR) and nuclear quadrupole resonance (NQR) on compounds with
Mn contents ranging from x=0.02... | 1401.7576v1 |
2014-01-30 | Electronic structure of BaNi$_2$P$_2$ observed by angle-resolved photoemission spectroscopy | We have performed an angle-resolved photoemission spectroscopy (ARPES) study
of BaNi$_2$P$_2$ which shows a superconducting transition at $T_c$ $\sim$ 2.5
K. We observed hole and electron Fermi surfaces (FSs) around the Brillouin zone
center and corner, respectively, and the shapes of the hole FSs dramatically
changed ... | 1401.7897v2 |
2014-01-31 | A global cloud map of the nearest known brown dwarf | Brown dwarfs -- substellar bodies more massive than planets but not massive
enough to initiate the sustained hydrogen fusion that powers self-luminous
stars -- are born hot and slowly cool as they age. As they cool below about
2,300 K, liquid or crystalline particles composed of calcium aluminates,
silicates and iron c... | 1401.8145v1 |
2014-02-01 | Phase stability and Nucleation effect upon Iron addition to SmCo5 bulk magnets | Change in structure and magnetic properties of SmCo5-xFex permanent magnets
for different values of x ranging from 0 to 2 have been studied. Structural
investigation from X-ray diffraction (XRD) patterns confirms the hexagonal
CaCu5-type structure of the SmCo5-xFex ribbons for 0<x<2. The decrease in
angular position of... | 1402.0138v1 |
2014-02-03 | Hemispherical Parker waves driven by thermal shear in planetary dynamos | Planetary and stellar magnetic fields are thought to be sustained by helical
motions ($\alpha$-effect) and, if present, differential rotation
($\Omega$-effect). In the Sun, the strong differential rotation in the
tachocline is responsible for an efficient $\Omega$-effect creating a strong
axisymmetric azimuthal magneti... | 1402.0343v1 |
2014-02-06 | Temperature-induced Change in the Fermi Surface Topology in the Spin Density Wave Phase of Sr(Fe$_{1-x}$Co$_x$)$_2$As$_2$ | We report electronic Raman scattering measurements of
Sr(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystals in their magnetic - Spin Density
Wave (SDW) phase. The spectra display multiple, polarization-resolved SDW gaps
as expected in a band-folding itinerant picture for a multiband system. The
temperature dependence of the S... | 1402.1422v2 |
2014-02-07 | Signatures of superconducting and pseudogap phases in ultrafast transient reflectivity of Ca(Fe0.927Co0.073)2As2 | We present femtosecond time-resolved pump-probe spectroscopic studies of a
pseudogap (PG) along with the superconducting (SC) gap in an overdoped iron
pnictide Ca(Fe0.927Co0.073)2As2. It is seen that the temperature evolution of
the photoexcited quasiparticle (QP) relaxation dynamics, coherently excited
A1g-symmetric o... | 1402.1627v1 |
2014-02-07 | Suzaku Discovery of Fe K-Shell Line from the O-Rich SNR G292.0+1.8 | We report the Suzaku/XIS results of the Galactic oxygen-rich supernova
remnant (SNR), G292.0+1.8, a remnant of a core-collapse supernova. The X-ray
spectrum of G292.0+1.8 consists of two type plasmas, one is in collisional
ionization equilibrium (CIE) and the other is in non-equilibrium ionization
(NEI). The CIE plasma... | 1402.1633v1 |
2014-02-12 | Electron Impact Ionization of Stored Highly Charged Ions | Accurate cross section data for electron impact ionization (EII) are needed
in order to interpret the spectra of collisionally ionized plasmas both in
astrophysics and in the laboratory. Models and spectroscopic diagnostics of
such plasmas rely on accurate ionization balance calculations, which depend, in
turn, on the ... | 1402.2964v1 |
2014-02-21 | Enhancement of Superconducting Transition Temperature Due to Antiferromagnetic Spin Fluctuations in Iron-pnictides LaFe(As_{1-x}P_x)(O_{1-y}F_y) : 31P-NMR Studies | Systematic P-NMR studies on LaFe(As_{1-x}P_x)(O_{1-y}F_y) with y=0.05 and 0.1
have revealed that the antiferromagnetic spin fluctuations (AFMSFs) at low
energies are markedly enhanced around x=0.6 and 0.4, respectively, and as a
result, Tc exhibits respective peaks at 24 K and 27 K against the
P-substitution for As. Th... | 1402.5220v1 |
2014-03-02 | Transport in multiband systems with hot spots on the Fermi surface: Forward-scattering corrections | Multiband models with hot spots are of current interest partly because of
their relevance for the iron-based superconductors. In these materials, the
momentum-dependent scattering off spin fluctuations and the ellipticity of the
electron Fermi pockets are responsible for anisotropy of the lifetimes of
excitations aroun... | 1403.0144v2 |
2014-03-02 | Heat transport in RbFe2As2 single crystal: evidence for nodal superconducting gap | The in-plane thermal conductivity of iron-based superconductor RbFe$_2$As$_2$
single crystal ($T_c \approx$ 2.1 K) was measured down to 100 mK. In zero
field, the observation of a significant residual linear term $\kappa_0/T$ =
0.65 mW K$^{-2}$ cm$^{-1}$ provides clear evidence for nodal superdonducting
gap. The field ... | 1403.0191v3 |
2014-03-02 | Nodeless superconducting gaps in Ca$_{10}$(Pt$_{4-δ}$As$_8$)((Fe$_{1-x}$Pt$_{x}$)$_2$As$_2$)$_5$ probed by quasiparticle heat transport | The in-plane thermal conductivity of iron-based superconductor
Ca$_{10}$(Pt$_{4-\delta}$As$_8$)((Fe$_{1-x}$Pt$_{x}$)$_2$As$_2$)$_5$ single
crystal (``10-4-8", $T_c$ = 22 K) was measured down to 80 mK. In zero field,
the residual linear term $\kappa_0/T$ is negligible, suggesting nodeless
superconducting gaps in this mu... | 1403.0194v1 |
2014-03-04 | Tunnel diode oscillator measurements of the upper critical magnetic field of FeTe0:5Se0:5 | Temperature dependence of the upper critical magnetic field (Hc2) of single
crystalline FeTe0.5Se0.5 (Tc = 14.5 K) have been determined by tunnel diode
oscillator-based measurements in magnetic fields of up to 55 T and temperatures
down to 1.6 K. The Werthamer-Helfand-Hohenberg model accounts for the data for
magnetic ... | 1403.0844v1 |
2014-03-05 | Design and demonstration of a quasi-monoenergetic neutron source | The design of a neutron source capable of producing 24 and 70 keV neutron
beams with narrow energy spread is presented. The source exploits
near-threshold kinematics of the $^{7}$Li(p,n)$^{7}$Be reaction while taking
advantage of the interference `notches' found in the scattering cross-sections
of iron. The design was ... | 1403.1285v2 |
2014-03-08 | High critical-current density with less anisotropy in BaFe2(As,P)2 epitaxial thin films: Effect of intentionally grown c-axis vortex-pinning centers | We report herein a high and isotropic critical-current density Jc for
BaFe2(As,P)2 epitaxial films. The isotropy of Jc with respect to the
magnetic-field direction was improved significantly by decreasing the film
growth rate to 2.2 {\AA}/s. The low growth rate served to preferentially align
dislocations along the c-ax... | 1403.1947v2 |
2014-03-08 | Challenges in nucleosynthesis of trans-iron elements | Nucleosynthesis beyond Fe poses additional challenges not encountered when
studying astrophysical processes involving light nuclei. Astrophysical sites
and conditions are not well known for some of the processes involved. On the
nuclear physics side, different approaches are required, both in theory and
experiment. The... | 1403.2015v1 |
2014-03-11 | Chemical abundance analysis of symbiotic giants. I. RW Hya and SY Mus | The study of symbiotic systems is of considerable importance in our
understanding of binary system stellar evolution in systems where mass loss or
transfer takes place. Elemental abundances are of special significance since
they can be used to track mass exchange. However, there are few symbiotic
giants for which the a... | 1403.2659v1 |
2014-03-22 | Neutron Reactions in Astrophysics | The quest for the origin of matter in the Universe had been the subject of
philosophical and theological debates over the history of mankind, but
quantitative answers could be found only by the scientific achievements of the
last century. A first important step on this way was the development of
spectral analysis by Ki... | 1403.5670v1 |
2014-03-24 | Dust formation in macronovae | We examine dust formation in macronovae (as known as kilonovae), which are
the bright ejecta of neutron star binary mergers and one of the leading sites
of r-process nucleosynthesis. We find that dust grains of r-process elements
are difficult to form because of the low number density of the r-process atoms,
while carb... | 1403.5872v2 |
2014-03-26 | Photoconductivity and photo-detection response of multiferroic bismuth iron oxide | We report visible light detection with in-plane BiFeO3 (BFO) thin films grown
on pre-patterned inter-digital electrodes. In-plane configured BFO film
displayed photocurrents with a 40:1 photo-to-dark-current ratio and improved
photo-sensing ability for >15000 s (4 hrs) under small bias voltage (42V).
Nearly sixty perce... | 1403.6748v1 |
2014-03-26 | Simulating a two-dimensional frustrated spin system with fermionic resonating-valence-bond states | The frustrated Heisenberg $J_{1}-J_{2}$ model on a square lattice is
numerically investigated by variational Monte Carlo simulations. We propose a
antiferromagnetic fermion resonating-valence-bond (AF-fRVB) state that has
ability to examine the entire phase diagram in the $J_{1}-J_{2}$ model. Two
phase transition point... | 1403.6879v1 |
2014-03-30 | Scattering of electron vortex beams on a magnetic crystal: towards atomic resolution magnetic measurements | Use of electron vortex beams (EVB), that is convergent electron beams
carrying an orbital angular momentum (OAM), is a novel development in the field
of transmission electron microscopy. They should allow measurement of
element-specific magnetic properties of thin crystals using electron magnetic
circular dichroism (EM... | 1403.7730v1 |
2014-03-31 | Strain effects on electronic structure and superconductivity in the iron telluride | The influence of tensile strain in the ab-plane on crystal and electronic
structure of FeTe has been studied ab initio. In superconducting FeSe the Fermi
surface nesting with a vector q~(0.5,0.5)(2\pi /a) is believed to be crucial
for rising superconductivity mediated by spin-fluctuations. The results
presented here in... | 1403.8005v2 |
2014-04-02 | Spurious peaks arising from multiple scattering events involving cryostat walls in inelastic neutron scattering | Well defined peaks with energies of about 18 meV have been observed in a
variety of inelastic neutron scattering experiments on single crystals as well
as on powders of iron-based superconductors and their parent compounds using
either the triple-axis or the time-of-flight technique. They can easily be
mistaken for sig... | 1404.0522v2 |
2014-04-03 | Charge Transfer Kinetics at the Solid-Solid Interface in Porous Electrodes | Interfacial charge transfer is widely assumed to obey Butler-Volmer kinetics.
For certain liquid-solid interfaces, Marcus-Hush-Chidsey theory is more
accurate and predictive, but it has not been applied to porous electrodes. Here
we report a simple method to extract the charge transfer rates in carbon-coated
LiFePO4 po... | 1404.0859v1 |
2014-04-03 | Fermi-Surface Reconstruction and Complex Phase Equilibria in CaFe$_{2}$As$_{2}$ | Fermi-surface topology governs the relationship between magnetism and
superconductivity in iron-based materials. Using low-temperature transport,
angle-resolved photoemission, and x-ray diffraction we show unambiguous
evidence of large Fermi surface reconstruction in CaFe$_{2}$As$_{2}$ at
magnetic spin-density-wave and... | 1404.1095v1 |
2014-04-07 | Fingerprints of Galactic Loop I on the Cosmic Microwave Background | We investigate possible imprints of galactic foreground structures such as
the "radio loops" in the derived maps of the cosmic microwave background.
Surprisingly there is evidence for these not only at radio frequencies through
their synchrotron radiation, but also at microwave frequencies where emission
by dust domina... | 1404.1899v3 |
2014-04-09 | Zinc abundances of planetary nebulae | Zinc is a useful surrogate element for measuring Fe/H as, unlike iron, it is
not depleted in the gas phase media. Zn/H and O/Zn ratios have been derived
using the [Zn IV] emission line at 3.625um for a sample of nine Galactic
planetary nebulae, seven of which are based upon new observations using the
VLT. Based on phot... | 1404.2524v1 |
2014-04-10 | Synthesis and physical properties of Ca1-xRExFeAs2 with RE = La ~ Gd | Synthesis of a series of layered iron arsenides Ca1-xRExFeAs2 (112) was
attempted by heating at 1000 C under a high-pressure of 2 GPa. The 112 phase
successfully forms with RE = La, Ce, Nd, Sm, Eu and Gd, while Tb, Dy and Ho
substituted and RE free samples does not contain the 112 phase. The Ce, Nd, Sm,
Eu and Gd doped... | 1404.2738v1 |
2014-04-24 | Superconductivity driven by the screening of long-distance Coulomb interaction | The pair-fluctuation contribution reduces the electrostatic screening length
in superconductivity as compared to the normal state. When a conductor
possesses a static background charge distribution, superconductivity arises
even in the absence of an explicit pairing interaction, such that the Coulomb
repulsion is reduc... | 1404.6292v1 |
2014-04-25 | An all-electrical torque differential magnetometer operating under ambient conditions | An all-electrical torque differential magnetometry (also known as cantilever
magnetometry) setup employing piezoelectric quartz tuning forks is
demonstrated. The magnetometer can be operated under ambient conditions as well
as low temperatures and pressures. It extends the allowed specimen mass range
up to several 10 $... | 1404.6341v2 |
2014-05-02 | Spectral line broadening in magnetized black holes | We consider weakly magnetized non-rotating black holes. In the presence of a
regular magnetic field the motion of charged particles in the vicinity of a
black hole is modified. As a result, the position of the innermost stable
circular orbit (ISCO) becomes closer to the horizon. When the Lorentz force is
repulsive (dir... | 1405.0510v3 |
2014-05-06 | Evolution from incoherent to coherent electronic states and its implications to superconductivity in FeTe1-xSex | We have performed systematic angle-resolved photoemission spectroscopy
(ARPES) of iron-chalcogenide superconductor FeTe1-xSex to elucidate the
electronic states relevant to the superconductivity. While the Fermi-surface
shape is nearly independent of x, we found that the ARPES spectral line shape
shows prominent x depe... | 1405.1172v1 |
2014-05-05 | Mathematical Modeling on Open Limestone Channel | Acid mine drainage (AMD) is the outflow of acidic water from metal mines or
coal mines. When exposed to air and water, metal sulfides from the deposits of
the mines are oxidized and produce acid, metal ions and sulfate, which lower
the pH value of the water. An open limestone channel (OLC) is a passive and low
cost way... | 1405.1338v1 |
2014-05-08 | Effect of nominal substitution of transition metals for excess Fe in Fe_{1+x}Se superconductor | Taking cue from the increase in the superconducting transition temperature
(Tc) of Fe1+xSe via nominal (2 wt%) substitution of Cr instead of excess Fe, we
have now extended our study with nominal substitution (<=5 wt%) with other
transition metals (Ni, Co, Fe, Mn, Cr, V and Ti) in place of excess iron. The
Tc is found ... | 1405.2050v3 |
2014-05-13 | Magnetism and superconductivity in Sr$_2$VFeAsO$_3$ revealed by $^{75}$As- and $^{51}$V-NMR under elevated pressures | We report $^{75}$As- and $^{51}$V-nuclear magnetic resonance (NMR)
measurements on the iron-based superconductor Sr$_2$VFeAsO$_3$ with alternating
stacks structure. We find that the $^{75}$As nuclear spin-spin relaxation rate
($1/T_2$) shows a pronounced peak at $T_N$ = 165 K, below which the resonance
peak shifts to a... | 1405.3048v1 |
2014-05-15 | Nuclear Target Cross Section Ratios at MINERvA | Measurements of $\nu_{\mu}$ inclusive charged-current cross section ratios on
carbon, iron, and lead relative to scintillator are presented. Data for the
analysis were collected by the fine-grained MINERvA detector in the NuMI
beamline at Fermilab. This is the first direct measurement of nuclear
dependence in neutrino ... | 1405.3960v1 |
2014-05-19 | Neutron Scattering Measurements of Spatially Anisotropic Magnetic Exchange Interactions in Semiconducting K0.85Fe1.54Se2 (TN=280 K) | We use neutron scattering to study the spin excitations associated with the
stripe antiferromagnetic (AFM) order in semiconducting
K$_{0.85}$Fe$_{1.54}$Se$_2$ ($T_N$=$280$ K). We show that the spin wave spectra
can be accurately described by an effective Heisenberg Hamiltonian with highly
anisotropic in-plane couplings... | 1405.4737v1 |
2014-05-19 | Multiferroic Iron Oxide Thin Films at Room-Temperature | In spite of being highly relevant for the development of a new generation of
information storage devices, not many single-phase materials displaying
magnetic and ferroelectric orders above room temperature are known. Moreover,
these uncommon materials typically display insignificant values of the remanent
moment in one... | 1405.4909v1 |
2014-05-22 | Layered water Cherenkov detector for the study of ultra high energy cosmic rays | We present a new design for the water Cherenkov detectors that are in use in
various cosmic ray observatories. This novel design can provide a significant
improvement in the independent measurement of the muonic and electromagnetic
component of extensive air showers. From such multi-component data an event by
event cla... | 1405.5699v1 |
2014-05-25 | Theory of Point Contact Spectroscopy in Correlated Materials | We develop a microscopic theory for the point-contact conductance between a
metalic electrode and a strongly correlated material using the non-equilibrium
Schwinger-Kadanoff-Baym-Keldysh formalism. We explicitly show that in the
classical limit, contact size shorter than the scattering length of the system,
the microsc... | 1405.6357v2 |
2014-05-25 | CaFeAs$_2$: a Staggered Intercalation of Quantum Spin Hall and High Temperature Superconductivity | We predict that CaFeAs$_2$, a newly discovered iron-based high temperature
(T$_c$) superconductor, is a staggered intercalation compound that integrates
topological quantum spin hall (QSH) and superconductivity (SC). CaFeAs$_2$ has
a structure with staggered CaAs and FeAs layers. While the FeAs layers are
known to be r... | 1405.6401v2 |
2014-05-28 | Contactless measurement of nonlinear conductivity in the radio-frequency range | We have developed a system for contactless measurement of nonlinear
conductivity in the radio-frequency band, and over a wide temperature range. A
non-resonant circuit is used to electrically excite the sample, and the induced
signal is detected by a resonant circuit whose natural frequency matches higher
harmonics of ... | 1405.7282v1 |
2014-05-31 | Point contact spectroscopy in the superconducting and normal state of $\mathrm{NaFe_{1-\textit{x}}Co_\textit{x}As}$ | We use point contact spectroscopy to probe the superconducting and normal
state properties of the iron-based superconductor
$\rm{NaFe_{1-\textit{x}}Co_{\textit{x}}As}$ with $\rm{\textit{x} = 0, 0.02,
0.06}$. Andreev spectra corresponding to multiple superconducting gaps are
detected in the superconducting phase. For $\... | 1406.0038v1 |
2014-06-01 | Hydrogen-Activation Mechanism of [Fe] Hydrogenase Revealed by Multi-Scale Modeling | When investigating the mode of hydrogen activation by [Fe] hydrogenases, not
only the chemical reactivity at the active site is of importance but also the
large-scale conformational change between the so-called open and closed
conformations, which leads to a special spatial arrangement of substrate and
iron cofactor. T... | 1406.0166v1 |
2014-06-04 | Observation of strong electron pairing on bands without Fermi surfaces in LiFe1-xCoxAs | In conventional BCS superconductors, the quantum condensation of
superconducting electron pairs is understood as a Fermi surface (FS)
instability, in which the low-energy electrons are paired by attractive
interactions. Whether this explanation is still valid in high-Tc
superconductors such as cuprates and iron-based s... | 1406.0983v2 |
2014-06-04 | Anomalous Nernst and Hall effects in magnetized platinum and palladium | We study the anomalous Nernst effect (ANE) and anomalous Hall effect (AHE) in
proximity-induced ferromagnetic palladium and platinum which is widely used in
spintronics, within the Berry phase formalism based on the relativistic band
structure calculations. We find that both the anomalous Hall ($\sigma_{xy}^A$)
and Ner... | 1406.1029v1 |
2014-06-09 | Magnetic and orbital instabilities in a lattice of SU(4) organometallic Kondo complexes | Motivated by experiments of scanning tunneling spectroscopy (STS) on
self-assembled networks of iron(II)-phtalocyanine (FePc) molecules deposited on
a clean Au(111) surface [FePc/Au(111)] and its explanation in terms of the
extension of the impurity SU(4) Anderson model to the lattice in the Kondo
regime, we study the ... | 1406.2347v1 |
2014-06-11 | ARPES experiment in fermiology of quasi-2D metals (Review Article) | Angle resolved photoemission spectroscopy (ARPES) enables direct observation
of the Fermi surface and underlying electronic structure of crystals---the
basic concepts to describe all the electronic properties of solids and to
understand the key electronic interactions involved. The method is the most
effective to study... | 1406.2948v1 |
2014-06-14 | Critical Behavior of the SDW Transition in Underdoped Ba(Fe1-xCox)2As2 (x <=0.05): 75As NMR Investigation | We investigate the nature of the SDW (Spin Density Wave) transition in the
underdoped regime of an iron-based high Tc superconductor Ba(Fe1-xCox)2As2 by
75As NMR, with primary focus on a composition with x = 0.02 (T_SDW = 99 K).We
demonstrate that critical slowing down toward the three dimensional SDW
transition sets i... | 1406.3734v1 |
2014-06-16 | Search for Magnetic Monopole using ICAL at INO | Sub-relativistic magnetic monopoles are predicted from the GUT era by theory.
To date there have been no confirmed observations of such exotic particles. The
Iron CALorimeter (ICAL) at India-based Neutrino Observatory (INO) aims to
measure the neutrino oscillation parameters precisely. As it is a tracking
detector ther... | 1406.3938v1 |
2014-06-16 | An air-cooled Litz wire coil for measuring the high frequency hysteresis loops of magnetic samples : a useful setup for magnetic hyperthermia applications | A low-cost and simple setup for measuring the high-frequency hysteresis loops
of magnetic samples is described. An AMF in the range 6-100 kHz with amplitude
up to 80 mT is produced by a Litz wire coil. The latter is air-cooled using a
forced-air approach so no water flow is required to run the setup.
High-frequency hys... | 1406.4013v1 |
2014-06-16 | Infrared dichroism of gold nanorods controlled using a magnetically addressable mesophase | Gold nanorods have unique optical properties, which make them promising
candidates for building nano-structured materials using a "bottom-up" strategy.
We formulate stable bulk materials with anisotropic optical properties by
inserting gold and iron oxide nanorods within a lamellar mesophase.
Quantitative measurements ... | 1406.4014v1 |
2014-06-21 | The Deaths of Very Massive Stars | The theory underlying the evolution and death of stars heavier than 10 Msun
on the main sequence is reviewed with an emphasis upon stars much heavier than
30 Msun. These are stars that, in the absence of substantial mass loss, are
expected to either produce black holes when they die, or, for helium cores
heavier than a... | 1406.5657v1 |
2014-06-22 | Variation of the X-ray non-thermal emission in the Arches cloud | The origin of the iron fluorescent line at 6.4 keV from an extended region
surrounding the Arches cluster is debated and the non-variability of this
emission up to 2009 has favored the low-energy cosmic-ray origin over a
possible irradiation by hard X-rays. By probing the variability of the Arches
cloud non-thermal emi... | 1406.5727v1 |
2014-06-22 | Putnam looks at quantum mechanics (again and again) | Hilary Putnam (1965, 2005) has argued that from a realist perspective,
quantum mechanics stands in need of an interpretation. Ironically, this
hypothesis may appear vulnerable against arguments drawing on Putnam's own
work. Nancy Cartwright (2005) has urged that his 1962 essay on the meaning of
theoretical terms sugges... | 1406.5737v1 |
2014-06-23 | Phonon Anomalies, Orbital-Ordering and Electronic Raman Scattering in iron-pnictide Ca(Fe0.97Co0.03)2As2: Temperature-dependent Raman Study | We report inelastic light scattering studies on Ca(Fe0.97Co0.03)2As2 in a
wide spectral range of 120-5200 cm-1 from 5K to 300K, covering the tetragonal
to orthorhombic structural transition as well as magnetic transition at Tsm ~
160K. The mode frequencies of two first-order Raman modes B1g and Eg, both
involving displ... | 1406.5844v1 |
2014-06-30 | Interplay of magnetism and superconductivity in EuFe$_{2}$(As$_{1-x}$P$_{x}$)$_{2}$ single crystals probed by muon spin rotation and ${}^{57}$Fe Mössbauer spectroscopy | We present our results of a local probe study on
EuFe$_{2}$(As$_{1-x}$P$_{x}$)$_{2}$ single crystals with $x$=0.13, 0.19 and
0.28 by means of muon spin rotation and ${}^{57}$Fe M\"ossbauer spectroscopy.
We focus our discussion on the sample with $x$=0.19 viz. at the optimal
substitution level, where bulk superconductiv... | 1406.7715v1 |
2014-06-30 | Theoretical Analysis of Bayesian Optimisation with Unknown Gaussian Process Hyper-Parameters | Bayesian optimisation has gained great popularity as a tool for optimising
the parameters of machine learning algorithms and models. Somewhat ironically,
setting up the hyper-parameters of Bayesian optimisation methods is notoriously
hard. While reasonable practical solutions have been advanced, they can often
fail to ... | 1406.7758v1 |
2014-07-01 | Emergent defect states as a source of resistivity anisotropy in the nematic phase of iron pnictides | We consider the role of potential scatterers in the nematic phase of Fe-based
superconductors above the transition temperature to the (pi,0) magnetic state
but below the orthorhombic structural transition. The anisotropic spin
fluctuations in this region can be frozen by disorder, to create elongated
magnetic droplets ... | 1407.0117v1 |
2014-07-01 | Anomalous ideal tensile strength of ferromagnetic Fe and Fe-rich alloys | Within the same failure mode, iron has the lowest ideal tensile strength
among the transition metals crystallizing in the body-centered cubic structure.
Here, we demonstrate that this anomalously low strength of Fe originates partly
from magnetism and is reflected in unexpected alloying effects in dilute
Fe(\emph{M}) (... | 1407.0289v1 |
2014-07-03 | The electronic structure of Co-substituted $\textrm{Fe}\textrm{Se}$ superconductor probed by soft X-ray spectroscopy and density functional theory | We study the crystalline and electronic properties of the
$\textrm{Fe}_{1-x}\textrm{Co}_x\textrm{Se}$ system ($x=0$, 0.25, 0.5, 0.75, and
1.0) using X-ray diffraction, X-ray spectroscopy and density functional theory.
We show that the introduction of Co $3d$ states in FeSe relaxes the bond
strengths and induces a struc... | 1407.0746v1 |
2014-07-03 | A Tale of Three Galaxies: Anomalous Dust Properties in IRASF10398+1455, IRASF21013-0739 and SDSSJ0808+3948 | On a galactic scale the 9.7um silicate emission is usually only seen in type
1 active galactic nuclei (AGNs). They usually also display a flat emission
continuum at ~5--8um and the absence of polycyclic aromatic hydrocarbon (PAH)
emission bands. In contrast, starburst galaxies, luminous infrared (IR)
galaxies (LIRGs), ... | 1407.0914v3 |
2014-07-03 | Superconductivity by rare earth doping in the 1038-type compounds (Ca$_{1-x}$RE$_x$)$_{10}$(FeAs)$_{10}$(Pt$_3$As$_8$) with RE = Y, La-Nd, Sm-Lu | We report superconductivity in polycrystalline samples of the 1038-type
compounds (Ca$_{1-x}$RE$_x$)$_{10}$(FeAs)$_{10}$(Pt$_3$As$_8$) up to T$_c$ = 35
K with RE = Y, La-Nd, Sm, Gd-Lu. The critical temperatures are independent of
the trivalent rare earth element used, yielding an universal T$_c$($x$) phase
diagram for ... | 1407.1007v1 |
2014-07-05 | Self-organized electronic superlattices in layered materials | We show that in layered systems with electronic phase separation tendency,
the long-range Coulomb interaction can drive the spontaneous formation of
unidirectional superlattices of electronic charge in a completely homogeneous
crystalline background. In this self-organized electronic heterostructure, the
ratio among th... | 1407.1378v1 |
2014-07-10 | NMR investigation of spin correlations in BaCo2As2 | We use NMR techniques to investigate the magnetic properties of BaCo2As2
single crystals, the non-superconducting end member of the Co-substituted
iron-pnictide high Tc superconductor Ba(Fe1-xCox)2As2 with x = 1. We present
75As NMR evidence for enhancement of low frequency spin fluctuations below ~
100 K. This enhance... | 1407.2750v1 |
2014-07-13 | Accurate bare susceptibilities from full-potential $\textit{ab initio}$ calculations | Electronic susceptibilities are a very popular tool to study electronic and
magnetic properties of materials, both in experiment and theory. Unfortunately,
the numerical evaluation of even the bare susceptibility, which depends on the
computation of matrix elements and sums over energy bands, is very
work-intensive and... | 1407.3444v2 |
2014-07-14 | Observation of pseudogap-like feature above Tc in LiFeAs and (Ba0.6K0.4)Fe2As2 by ultrafast optical measurement | We utilize ultrafast optical measurement to study the quasiparticle
relaxation in stoichiometric LiFeAs and nearly optimally doped (BaK)Fe2As2
crystals. According to our temperature-dependent studies of LiFeAs, we have
observed pseudogap-like feature at onset temperature of ~ 55 K, which is above
Tc = 15 K. In addition... | 1407.3539v1 |
2014-07-16 | The Effect of Doppler Broadening on the $6.3 \ PeV$ $W^-$ Resonance in $\barν_e e^-$ Collisions | We calculate the Doppler broadening of the $W^-$ resonance produced in
$\bar{\nu}_e e^-$ collisions of cosmic anti-neutrinos with $E_{\nu}\approx 6.3
\ PeV$ with electrons in atoms up to Iron. Revisiting this issue is prompted by
recent observations of PeV neutrinos by Ice-Cube. Despite its poor energy
resolution, the ... | 1407.4415v1 |
2014-07-17 | Spatial ordering of nano-dislocation loops in ion-irradiated materials | Defect microstructures formed in ion-irradiated metals, for example iron or
tungsten, often exhibit patterns of spatially ordered nano-scale dislocation
loops. We show that such ordered dislocation loop structures may form
spontaneously as a result of Brownian motion of loops, biased by the
angular-dependent elastic in... | 1407.4683v1 |
2014-07-18 | Estimating R-Process Yields from Abundances of the Metal-Poor Stars | The chemical abundances of metal-poor stars provide important clues to
explore stellar formation history and set significant constraints on models of
the r-process. In this work, we find that the abundance patterns of the light
and iron group elements of the main r-process stars are very close to those of
the weak r-pr... | 1407.4878v1 |
2014-07-22 | Orbital Selective Mott Transition Induced by Orbitals with Distinct Noninteracting Densities of States | By applying dynamical mean-field theory in combination with exact
diagonalization at zero temperature to a half-filled Hubbard model with two
orbitals having distinct noninteracting densities of states, we show that an
orbital selective Mott transition (OSMT) will take place even without crystal
field splitting, differ... | 1407.5795v1 |
2014-07-31 | Improving the Scalability of DPWS-Based Networked Infrastructures | The Devices Profile for Web Services (DPWS) specification enables seamless
discovery, configuration, and interoperability of networked devices in various
settings, ranging from home automation and multimedia to manufacturing
equipment and data centers. Unfortunately, the sheer simplicity of event
notification mechanism... | 1407.8546v1 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.